Tuesday, April 21, 2009
Tuesday, March 31, 2009
Gravitation and the Force of Gravity
by Ron Kurtus (revised 2 September 2007)
Although many had previously studied the effect of gravitation, where objects seem to be attracted to the ground, it wasn't until Isaac Newton formulated the Theory of Universal Gravitation that the phenomenon could be explained and predicted. He defined gravity as a force that acts at a distance and attracts bodies of matter toward each other. Years later, Albert Einstein developed a completely different theory of gravitation in his Theory of Relativity, saying it was due to a curvature in space. Modern theories try to explain gravitation with gravity particles or waves.
Questions you may have include:
How did Newton discover gravity?
How do we experience gravity?
What is the influence of gravity in the Universe?
This lesson will answer those questions. There is a mini-quiz near the end of the lesson.
information from this web page
http://www.school-for-champions.com/science/gravity.htm
by Ron Kurtus (revised 2 September 2007)
Although many had previously studied the effect of gravitation, where objects seem to be attracted to the ground, it wasn't until Isaac Newton formulated the Theory of Universal Gravitation that the phenomenon could be explained and predicted. He defined gravity as a force that acts at a distance and attracts bodies of matter toward each other. Years later, Albert Einstein developed a completely different theory of gravitation in his Theory of Relativity, saying it was due to a curvature in space. Modern theories try to explain gravitation with gravity particles or waves.
Questions you may have include:
How did Newton discover gravity?
How do we experience gravity?
What is the influence of gravity in the Universe?
This lesson will answer those questions. There is a mini-quiz near the end of the lesson.
information from this web page
http://www.school-for-champions.com/science/gravity.htm
Tuesday, March 10, 2009
In physics, a force is that which can cause an object with mass to change its velocity.[1] Force has both magnitude and direction, making it a vector quantity. Newton's second law states that an object with a constant mass will accelerate in proportion to the net force acting upon and in inverse proportion to its mass. Equivalently, the net force on an object equals the rate at which its momentum changes.[2]
Forces acting on three-dimensional objects may also cause them to rotate or deform, or result in a change in pressure or even change volume in some cases. The tendency of a force to cause changes in rotational speed about an axis is called torque. Deformation and pressure are the result of stress forces within an object.[3][4]
Since antiquity, scientists have used the concept of force in the study of stationary and moving objects. The study of forces advanced with descriptions made by the third century BC philosopher Archimedes of how forces interact in simple machines.[5] Prior to this, descriptions of forces by Aristotle incorporated fundamental misunderstandings. By the seventeenth century, Sir Issac Newton corrected these misunderstandings with mathematical insight that remained unchanged for nearly three hundred years.[4] By the early 20th century, Einstein in his theory of general relativity successfully predicted the failure of Newton's model for gravity by ushering in the concept of a space-time continuum.
The recent theory of particle physics known as the Standard Model associate forces at the level of quantum mechanics. The Standard Model predicts that exchange particles called gauge bosons are the fundamental means by which forces are emitted and absorbed. Only four main interactions are known: in order of decreasing strength, they are: strong, electromagnetic, weak, and gravitational.[3] High-energy particle physics observations made during the 1970s and 1980s confirmed that the weak and electromagnetic forces are expressions of a more fundamental electroweak interaction.[6] (fromhttp://en.wikipedia.org/wiki/Force)
Forces acting on three-dimensional objects may also cause them to rotate or deform, or result in a change in pressure or even change volume in some cases. The tendency of a force to cause changes in rotational speed about an axis is called torque. Deformation and pressure are the result of stress forces within an object.[3][4]
Since antiquity, scientists have used the concept of force in the study of stationary and moving objects. The study of forces advanced with descriptions made by the third century BC philosopher Archimedes of how forces interact in simple machines.[5] Prior to this, descriptions of forces by Aristotle incorporated fundamental misunderstandings. By the seventeenth century, Sir Issac Newton corrected these misunderstandings with mathematical insight that remained unchanged for nearly three hundred years.[4] By the early 20th century, Einstein in his theory of general relativity successfully predicted the failure of Newton's model for gravity by ushering in the concept of a space-time continuum.
The recent theory of particle physics known as the Standard Model associate forces at the level of quantum mechanics. The Standard Model predicts that exchange particles called gauge bosons are the fundamental means by which forces are emitted and absorbed. Only four main interactions are known: in order of decreasing strength, they are: strong, electromagnetic, weak, and gravitational.[3] High-energy particle physics observations made during the 1970s and 1980s confirmed that the weak and electromagnetic forces are expressions of a more fundamental electroweak interaction.[6] (fromhttp://en.wikipedia.org/wiki/Force)
Tuesday, March 3, 2009
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